Hatzenbach

Hi,

I just upgraded from my 330 mm stock rotors to 350 mm floating Girodisc rotors (thanks to the sale at Competition Motorsports).
I kept the OEM calipers, which means that there are now to "rings" (on the inside and outside) where the pads don't make contact.

That being said, now the question:
I am (one of these "crazy guys", who is) driving his car in the rain. Will the two rings eventually turn ugly rust brown?

nwGTS

Probably since they are not in the swept area. Can you explain how this is an upgrade if you did not upgrade the caliper size? I'm also curious as to how the caliper fits over the new rotor without striking the caliper bridge since you have the OEM caliper but an increased rotor size. It seems you may have but can you confirm you have installed these already without fitment issues?

namronorman

It's my understanding the caliper is remounted with a spacer to account for the larger diameter rotor.

Hatzenbach

Correct, you use a spacer (and longer bolts) to add clearance.
The caliper still clears 19" (street) and 18" (track) rims.

Why do I think this is an upgrade?
Well, my original setup had enough stopping power, that's not the problem.
However, I am (was?) struggling with heat on the track.
Even with GT2 brake ducts the brakes got simply too hot (Pagid Yellow up front and Orange in the rear)

So I was hoping that two items in this upgrade would help with heat dissipation
a) the two piece floating rotor design
b) the fact that a larger rotor can dissipate more heat

Cheers

nwGTS

I had heard similar regarding (b) but not seen data to back this up. Hope it works out for you and thanks for sharing.

slicky rick

Hatzen, the 350 is for the turbo yes? Would it have been better if the upgrade include turbo calipers? This would also solve your rusty lines problem. You can just sell your calipers for the same amount you get for the turbo ones...just thinking

PJorgen

Since the caliper is now further from the center of the wheel, the lever arm has been lengthened, so you should have more stopping power. Don't know the details of this setup so I don't know if the increase is significant. Maybe someone from Girodisc can jump in with more info?

Petza914

The larger rotor should provide a larger heat sink, but the purpose of a two-piece rotor, I believe, is primarily to reduce weight. I'm not sure what transfers as well between the iron rotor and aluminum hat as it does through a solid iron 1-piece rotor. I also would have thought that a proper upgrade kit might allow for a larger pad to have more swept rotor area. I think you should finish the job and upgrade the calipers and pads too as others have suggested.

Anyone, feel free to correct my understanding of the thermodynamics here with regard to heat sink and transfer.

Thanks.

NAM VET

one problem you are going to have is removing the present pads when the outer "lip" gets big enough to hinder pulling the pads out. I have had a variety of brake systems on my cars over the years, and it was always a hassle to switch pads when the whole rotor was not swept. I have no opinion on the other suggestions posted above.

all the best....

NV

Petza914

Any photos you can post?

Cloudspin

I've used the Giro 350s on my C2S for several years now. I started out using Pagid pads (yellow) with them and was somewhat underwhelmed with the minimal improvement over stock. I switched to PFC08s f&r after reading multiple posts on the GT3 forum and talking to Clark at RL Sponsor Apex Performance. They made a very significant difference. I've used them since. Randy Pobst drove my car at Sebring prior to most of my suspension tweaks and said multiple times how great the brakes were.

ive been through several sets of rings and now have a spare set of front hats so I always have a built up spare set of front rotors. I'm wearing fronts at approximately 2.5 times the rate of rears. I also sometimes get the rings you are describing after changing rings or pads but they always disappear after one track session. Have you done a track day since switching to the Giros?

cosanchez

You will get better heat dissipation with the larger rotor, but it's not ideal. You will have a large thermal gradient in the radial direction. Has anyone done this? It might mean you get a warped rotor if you really push it.

Hatzenbach

Hi, thanks.
I just installed them, and my track season is pretty much over. So I won't take them on the track before next spring. So you are saying I will have to deal with ugly rusty rings, but they will go away after a track session?

Hatzenbach

Will post some pics on the weekend

scorcherjf

I'm considering doing the same upgrade since the OEM rotors just crack from the stupid holes (using PF08 pads). I don't think the unswept areas rusting would bother me since it's just superficial. I'd rather have rust rings with the Girodiscs over tons of hairline cracks from the drill holes in the OEM rotors.